Authorities are no longer confident that they have a strong case against a 14-year-old boy accused in a drive-by shooting that killed four people in the District, and they might move to dismiss the charges against the youth, law enforcement and D.C. government sources said.

The full extent of the trouble with the case remains unclear, but one problem concerns insufficient evidence that the teenager was involved in the attack at all, according to the sources, who spoke on the condition of anonymity because the investigation is continuing.

Although a police sergeant identified the youth as the person she saw driving the minivan used in the March 30 attack, one of two adults who allegedly were in the van has told homicide detectives that the teenager was not with them, one of the sources said.